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The Ultra-Wide Promise of UWB
Issue #93 | March 9, 2007 | by Erik Wood
Promises, promises. . . that was essentially the song sung about Real Time Location [and Tracking] Systems (RTLS) over the last five or ten years by a chorus of RFID hardware, software and solutions companies. I should know – I was singing right along with them.
Today the rate of RTLS adoption is finally turning up the "hockey stick" curve. Has the technology really become any more effective today than three years ago? At that time, money was pouring out of bleeding edge solution providers with little to show for it.
Recent activities and announcements of RTLS implementations have been significant. Now hospitals, IT asset management, and manufacturing work in process (WIP) customers have been paying serious dough for honest-to-goodness, full scale roll outs that actually work after pilots have proven the return on investment (ROI).
The promise of each project is based on real estimates of cost savings and improvements to operational efficiencies, with measurable ROI. For example, some hospitals are now looking at the value of linking real-time location to track doctors, nurses, patients and hospital equipment, synching that data to patient billing systems. When their accounting can "automagically" be processed without manual input by humans. If that really works and case studies show the astounding savings – hold onto your socks, my friends!
About two weeks ago, the European Union issued a "harmonizing decision" defining how one can use the Ultra Wide Band. According to Ubisense, a growing player in this space out of Cambridge, England, the net result "approves general usage" of UWB. I’ve attached details provided by the EU which explains it better than I can.
EU Doc here
As I read the EU release, I was curious about the enthusiastic tone of their explanation. As excited as I am about RTLS kicking in gear, it is mostly by comparison to the six years I spent earning my living in the 433 MHz space making those promises. I still see no real delivery today. My firm belief this will all explode is straight from my belief in the technology paradigm. When it comes to truly useful technology, all it takes is time and money. This will certainly spur more widespread adoption and make the promise real. Meanwhile, the leading technology providers will be investing the money to get us there.
Three wireless choices
Let’s take a moment to back up and talk shop and technology landscape. The three wireless technology approaches in RTLS are 433MHz, 802.11 (2.4GHz), and Ultra Wide Band (UWB). All three use either RSSI or TDOA as the basis for triangulation, but I won’t go into those differences here. That is an entire story itself.
433MHz tags, then and now, are the lowest cost, smallest footprint, and least power-hungry of the three. I could make the case, and I used to regularly, that 433 is the true frequency sweet spot for measuring signal strength. But with the limitation of multipath and environmentally impacting dynamics, anything close to room to room delineation is just a dream. The major 433MHz providers recognize this, as well. They have added IR and acoustic sensing to the tags, in order to be able to claim room to room separation. Two of the leaders in this approach are RF Code and WaveTrend.
802.11 (wi-fi as most people know it) is arguably the most relevant today, not because of its technology prowess but because of it broad adoption. This is largely due to Cisco, the 800-pound gorilla in wireless IT, who has made the frequency of 2.4GHz and standard of 802.11 ubiquitous in business and has become a de facto standard. Two of the leaders, innovating new solutions with this technology, are AeroScout and Ekahau. You can connect directly to them through Switchboard’s Provider Directory: www.rfidsb.com/userpage.php?do=list
Most hospitals, many corporate enterprises and the manufacturing market all use wi-fi. With a significant installed base of wi-fi access points to read the signals, it is a natural choice for those enterprises. To compete against such a reality, a significant technology must fulfill the ultimate RTLS promise in a dramatic way.
Enter UWB. In my presentations of the past, UWB was always this nebulous contender, years away from being a reality. But what a reality it promised. While 433MHz and 802.11 jockey for the time-to-market play, both promoting 10-foot square locationing on an X & Y coordinate mapping GUI, UWB was quietly dealing with it’s market barriers.
While 433MHz has the better tag value strength with its maturity, power, and size benefits; and 802.11 has the better selling strength owing the install base; UWB has more promise of bottom line functionality for pure RTLS.
Using its very low power across a wide band of frequencies (unlike specific 433MHz or 2.4 GHz), UWB promises precise RTLS resolution. Already Ubisense is offering accuracy to within 15cm, or about six inches. And the promise is not only of X & Y coordinate inches, but also the Z.
Imagine a hummingbird floating through the air and you will understand the relative accuracy of this promise. Clearly software refresh rates will be a limiting factor on how this will translate on the viewable computer screen. ISO has defined real-time by updates at least every 30 seconds.
The barriers to the UWB approach were, and are, significant. The regulatory restrictions are onerous, despite the recent EU ruling. In the U.S., you need a waiver from the FCC to implement, since critical safety services use this band. As with most emerging power-consuming technologies, the batteries, and thus the tags, are big due to power requirements. Also, the cost of the tags are competitively high. While 433MHz tags are ~$10, UWB tags are up to 5X times that today.
Jay Cadman of Ubisense tells us they already have 170 active clients, mostly logistics and manufacturing buyers across the board, from medical devices to aerospace. Jay told us the biggest success customers are having is "understanding complex processes and determining where problems occur." And that’s no small thing.
Last edited by sanhan : 03-09-2007 at 01:35 PM.
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